The SY4 is only found on this car; it stands for Smokey Yunick 4 Cylinder.
Now for the video!
https://www.youtube.com/watch?v=Qg8oJXcWjnE
This Fiero was modified by Smokey Yunick and gets 51 mpg while going 0 to 60 in 5 sec. Why wasn't it ever put into production? see more at
www.legendarycollectorcars.com
It would have destroyed the Corvette